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Topic Review (Newest First)

04-21-2009 03:19 PM

noelex77

Titanium causes less galvanic problems than its position on the galvanic series would suggest because the titanium oxide coating is less electrically conductive than ss.
There is ,however, no need for titanium in this application unpainted marine alumium wont corode as long as you isotate the disimalar metals. Duralac is simple and effective.
The genset may need to be electrically isolated from the negative pole

04-21-2009 02:43 PM

mepsnbarry

Titanium screws do sound like an interesting idea here, but they probably won't help corrosion as much as you think.

I just checked a galvanic series chart, and found that they are slightly worse than stainless in this regard--they are above stainless on the chart, or in other words, FARTHER from aluminum on the chart.

It is possible that the corrosion that forms between aluminum and titanium is less of a problem than the stuff that makes such a mess out of aluminum with stainless fasteners, but I wouldn't even count on that--I believe it is the less noble metal (aluminum) which corrodes, so I expect it will form the same oxides.

Perhaps Ti are strong enough to unscrew rather than shearing off like SS bolts do though?

If anybody has seen what Ti fasteners in Al look like after 10 years in a salty environment, let us know!

Has anyone given much thought to titanium fasteners, they aren't that mush more in cost, but 2/3rds less in weight and 2/3rds more in strength and you wont have the galvanic issues.

All my race bikes had all the fasteners, axles, pinion pins the works replaced with TI and never had a corrosion issues between the TI & ALU, not to mention I shed about 7-10 pounds off the bike.

I'm bet'n their some poundage that could be shed off the spars and even deck hardware fasteners

Just a thought

That is an intriguing thought. Even a half pound saved aloft could make some difference on my little boat. The published displacement is only 2000 lbs.

I did a quick Google search for titanium fasteners and did not find what I would need: (3) 3/8" x 4" bolts w/nyloc nuts. All of the sites I checked out had either smaller diameter/shorter lengths or they only sold industrial quantities. Where could I find appropriate titanium fittings w/o breaking the bank?

11-17-2008 08:18 PM

sailingdog

While titanium doesn't corrode too readily... it does cause serious galvanic corrosion issues when in close proximity to less noble metals in a saltwater situation.

For some reason, I doubt your bike was used much in a salt water environment.

Has anyone given much thought to titanium fasteners, they aren't that mush more in cost, but 2/3rds less in weight and 2/3rds more in strength and you wont have the galvanic issues.

All my race bikes had all the fasteners, axles, pinion pins the works replaced with TI and never had a corrosion issues between the TI & ALU, not to mention I shed about 7-10 pounds off the bike.

I'm bet'n their some poundage that could be shed off the spars and even deck hardware fasteners

Just a thought

11-17-2008 08:17 PM

trintella49

Aluminum Vessels

Dissimilar metals are enemies forever (even similar metals do not like each other) Paints and other covers are very difficult to cover aluminum. I suggest, unless you absolutely have to do not do it.
I have an aluminum sailing vessel (Trintella49A).
All possible means and methods were taken to place a barrier between the Alu structure and components.
The Generators sit atop of Wood. The wooden platform connectors have no direct connection with the Generator and Ships Frame.
Another major concern must be the electrical connections / Grounding (Floating) from the generators to the rest of the electrical and electronic systems. Be very careful.
Happy to give you some of my insight.

Regards, charles

11-17-2008 07:31 PM

CharlieCobra

You can probably get them from an Auto Paint supplier. The Alumagrip? It's been a while but it's a US Paint product, the same company that makes Awlgrip.

11-17-2008 07:25 PM

poopdeckpappy

LOL, it was a in general type thought, but in the back of your mind, do you really want to get beat by that 35999 lb boat.........I think not

11-17-2008 07:15 PM

svindigo

Hello Charlie - Thanks for the detail. It's more than I was planning to do but I'd like to do it right if it's to be done. I can find the zinc chromate primer but are the other items readily available to non aviation mechs?

Hi Xort, the only source of saltwater would be from a leak otherwise it should remain dry. Isolation is on the list of things to accomplish one way or the other in this job. It's not an aesthetic project but I want it to look good when done (and for some time afterward)

Pappy - While I agree with your logic and experience on bikes it probably wouldn't be worth it for me. The weight savings would go unnoticed in our 36000 lb baby unless it was part of a comprehensive Ti upgrade. As it is I'll be using 4 bolts to secure the generator to the Al frame.

If the fasteners are stainless steel, don't forget to use isolation washers of thin plastic and either TEFGEL or LANOCOTE on the bolts themselves to help prevent galvanic issues between the aluminum and stainless steel.

Has anyone given much thought to titanium fasteners, they aren't that mush more in cost, but 2/3rds less in weight and 2/3rds more in strength and you wont have the galvanic issues.

All my race bikes had all the fasteners, axles, pinion pins the works replaced with TI and never had a corrosion issues between the TI & ALU, not to mention I shed about 7-10 pounds off the bike.

I'm bet'n their some poundage that could be shed off the spars and even deck hardware fasteners

Just a thought

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